You don't need to be a hardcore rider to get the benefits of tubeless, and you already have all the expensive stuff already, your bike should have come with the valves even. It works out a similar price to replacing a couple of tubes a year, pretty cost effective. As already stated, seating the first time is much easier with a compressor and some tyres won't seat at all without one, but otherwise it's dead easy.
Are you getting new tyres or converting her already used ones? I ask because a tyre that has already been used with tubes with generally seat more easily, but sometimes will have picked up small holes in the casing that will make the initial seal more difficult. No big deal though, worst case scenario if it doesn't hold you can just throw a tube back in until it's new tyre time. (Edit: Just saw you were looking at new tyres)
Be aware also that generally tubeless setups lose air more quickly, ie you will definitely want to be checking pressure before each ride. Again, not a big deal, and there's no way I would go back to tubes. Probably the biggest advancement in mountainbike tech in the last 15 years an it's such a simple thing!
If you really feel that the bike shop is "just out to sell you something" you need a better bike shop. I've worked in shops for 20 years and although there definitely is that attitude in many shops, particularly the larger high-volume places, good shops will not tolerate a salesperson like that and they get weeded out very quickly as our reputation is on the line. You might pay a little bit more at a good place - because we don't shift the sheer number of units that the huge shops do - but the genuine advice we can offer is well worth it. I won't try and sell you a $500 part without letting you know about the $50 option too, and if the $50 part is actually a better choice for you I'll recommend it over the $500 one.
I get very frustrated when I see customers ignore my advice because they inherently mistrust anyone in a shop, and then it goes on to cost them more money or hassle/problems they could have avoided. It happens a lot, and it doesn't need to.